What is your definition of "professional quality"? There are plenty of advanced dslr like point and shoot cameras on the market these days that will give awesome results. You can find some excellent ones for under $300. They come with zooms up to 12X and more and plenty of megapixels and 3 fps in high speed. They have manual settings for total control by the photographer. This may not be such a bad way for your wife to get started. Unless she is going to open a studio or go into this as a profession, she may be totally happy with this type of setup.

But, if you have the bucks and don't mind spending them on speculation, $600 will buy you a good camera, without a lens. Good lenses can run aywhere from a few hundred to many thousands. Also, for most people, one or two lenses is never enough.